The present invention relates to rolling bearings, for example, a rolling bearing suitable for use with spindles of hard disk drives (HDDs), small-sized spindles for dental handpieces and the like.
Conventionally, as this type of rolling bearing, there has been available a rolling bearing comprising inner and outer rings made of bearing steel, and balls made of silicon nitride. Because the balls are made of silicon nitride, this bearing is advantageous in being capable of high-speed rotation and free from replenishment of grease for a long time.
However, in the conventional bearing as described above, although the intervals for replenishment of grease during high-speed rotation can be prolonged, that is, prolonged life of grease can be achieved, there has been a problem that increased vibrations and noise would be involved, as compared with bearings made fully of bearing steel, because the contact surface pressure between bearing steel and silicon nitride is higher than the contact surface pressure of bearings in which the inner and outer rings and the balls are both made of bearing steel.